sea dog—
1. an experienced sailor:
- In his blue Guernsey sweater he looked every bit an old sea dog.
2. a seal or a small sea lion:
- Its skin was rough, scaly, and grating, like that of a sea-dog or seal.
3. any of various small sharks:
- The chief fisheries are those of the tunny, of the sword fish, and of the sea dog, a species of shark.
4. (also: sea wolf ) a sea-robber; a pirate:
- The galleons of the Spanish Armada were pulled down by the sea-dogs of Drake.
water dog—
1. a dog trained to retrieve waterfowl:
- Though excellent water dogs … we have had to complain of their impetuous rush into pond or river.
2. (coll.) a good swimmer:
- I was the only water-dog of our band; neither Percy nor Captain Roberts nor the mate could swim.
3. (coll.) a good sailor:
- They [Sandwich Islanders] are complete water-dogs, and therefore very good in boating.
4. (pl., coll.) small dark floating clouds, forecasting rain:
- Reports of smoke were determined to be low lying haze and moisture (commonly called water dogs).